Pressure sensor and preparation method thereof

Abstract

The invention discloses a pressure sensor and a preparation method thereof, and relates to the technical field of sensors, the pressure sensor comprises a base, a measuring assembly, an insulating solid packaging layer and a pressure mouthpiece, a first end of the base is provided with a groove cavity, a second end of the base is provided with a wire hole communicated with the groove cavity, the measuring assembly comprises a chip and a wire, and the insulating solid packaging layer is arranged in the groove cavity. The chip is arranged in the groove cavity, a plurality of wires are electrically connected to the chip, any wire penetrates through the wire hole, the insulating solid packaging layer is arranged in the groove cavity, and the measuring assembly is packaged and fixed in the groove cavity; and the pressure mouthpiece is connected to the first end of the base in a sealing manner and is used for introducing the fluid to be measured into the groove cavity. According to the invention, the structural design of the non-oil-filled sensor is adopted, that is, the insulating solid packaging layer, which is a solid material in the groove cavity, is adopted as a pressure transmission medium, so that the problems of low output precision, low response speed, high oil leakage risk, narrow working temperature area, short service life and the like of a traditional oil-filled pressure sensor can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and particularly to a novel pressure sensor and a preparation method thereof. Background Art

[0002] Traditional pressure sensors mostly have an oil-filled structure. The silicone oil expands when working at high temperatures and contracts when working at low temperatures. This not only affects the output accuracy and stability of the pressure sensor, making the response speed of the pressure sensor slow and unable to meet the requirements of high-precision and rapid measurement, but also has a narrow working temperature range, limiting the application scope of the sensor. In addition, there is a risk of oil leakage during long-term operation of the oil-filled pressure sensor, which may lead to measurement errors or equipment damage, reducing the service life of the sensor.

[0003] Therefore, it is necessary to develop a novel pressure sensor to overcome the problems of low output accuracy, large measurement error, poor output stability, slow response speed, narrow working temperature range, high risk of liquid leakage, and low service life existing in the above-mentioned oil-filled pressure sensors. Summary of the Invention

[0004] The object of the present invention is to provide a novel pressure sensor and a preparation method thereof. The pressure sensor adopts a non-oil-filled structure design to solve the problems of low output accuracy, large measurement error, poor output stability, slow response speed, narrow working temperature range, high risk of liquid leakage, and low service life existing in the above-mentioned oil-filled pressure sensors.

[0005] To achieve the above object, the present invention provides the following solution: On the one hand, the present invention provides a pressure sensor, including a base, a measurement component, an insulating solid encapsulation layer, and a pressure nozzle; a groove cavity is provided at the first end of the base, and a wire hole communicating with the groove cavity is opened at the second end of the base; the measurement component includes a chip and a wire, the chip is disposed in the groove cavity, multiple wires are electrically connected to the chip, and any one of the wires passes through the wire hole and extends out of the base; the insulating solid encapsulation layer is disposed in the groove cavity and encapsulates and fixes the measurement component in the groove cavity; the pressure nozzle is sealingly connected to the first end of the base, and the pressure nozzle is used to introduce a fluid to be measured into the groove cavity.

[0006] Preferably, the insulating solid encapsulation layer is a silicone gel encapsulation layer.

[0007] Preferably, both the base and the pressure nozzle are made of titanium alloy structure, and the base and the pressure nozzle are welded.

[0008] Preferably, the base is a cylindrical base, and a plurality of the wire holes are uniformly formed around the axis of the second end of the cylindrical base; the number of the wires is the same as that of the wire holes, and one wire penetrates through any one of the wire holes.

[0009] Preferably, a sintered glass insulating layer is hermetically filled in the annular gap between any one of the wires and the corresponding wire hole.

[0010] Preferably, the pressure sensor further includes an insulating ceramic ring, which is arranged in the cavity of the groove, and ceramic holes corresponding to the wire holes one by one are formed in the insulating ceramic ring; the wires sequentially penetrate through the ceramic holes and the wire holes; the insulating ceramic ring is hermetically packaged and fixed in the cavity of the groove through the insulating solid packaging layer.

[0011] Preferably, a plurality of electrodes equal in number to the wires are arranged on one side end face of the chip facing the pressure nozzle, and any one of the wires is electrically connected to the corresponding electrode through a gold wire; and any one of the gold wires is arranged at an interval from the insulating ceramic ring.

[0012] Preferably, both the insulating ceramic ring and the chip are bonded in the cavity of the groove through an adhesive layer; the chip is located at the center of the insulating ceramic ring, and the electrode mounting end face of the chip protrudes from the inner ring end face of the insulating ceramic ring, and the inner ring end face is the inner ring part of one side end face of the insulating ceramic ring facing the pressure nozzle.

[0013] Preferably, the pressure nozzle includes a connection seat and a nozzle, the connection seat is hermetically connected to the first end of the base, a buffer cavity hermetically docked with the cavity of the groove is arranged at the first end of the connection seat, and the nozzle is arranged at the second end of the connection seat; a diversion hole is formed in the pressure nozzle, one end of the diversion hole penetrates through the connection seat and communicates with the buffer cavity, and the other end of the diversion hole penetrates through the nozzle; an external thread section is arranged at the end of the nozzle away from the connection seat; an annular groove for installing a sealing gasket is arranged between the external thread section and the connection seat.

[0014] On the other hand, the present invention provides a preparation method of the pressure sensor, including: threading the wires into the wire holes of the base; installing the chip in the cavity of the groove; installing the insulating ceramic ring in the cavity of the groove and making the wires extend into the ceramic holes; connecting and conducting the wires and the electrodes on the chip through a gold wire bonding technology; pouring silicone gel into the cavity of the groove and drying it to form the insulating solid packaging layer; welding the base and the pressure nozzle.

[0015] Preferably, vacuum electron beam welding is adopted between the base and the pressure nozzle.

[0016] The present invention has achieved the following technical effects compared with the prior art: The pressure sensor proposed by the present invention adopts a non-oil-filled sensor structure design, that is, an insulating solid encapsulation layer in a groove cavity is used as a solid material for pressure transmission, which can avoid the problems existing in traditional oil-filled pressure sensors, such as low output accuracy, large measurement error, poor output stability, slow response speed, high oil leakage risk, and low service life, and avoid the pollution and safety hazards brought by oil leakage. The measurement performance of the oil-filled pressure sensor is closely related to the ambient temperature, especially it is prone to failure at high temperatures, which greatly limits the application scenarios of the sensor; while the present invention uses a solid material to transmit pressure, which is less affected by the ambient temperature and can still maintain stable performance at high temperatures, with high measurement accuracy, and broadens the working temperature range of the sensor, improving the performance indicators of the pressure sensor and meeting the needs of more occasions with high-precision and wide-temperature-range layouts.

[0017] In some technical solutions disclosed by the present invention, both the base and the pressure nozzle of the pressure sensor are made of titanium alloy material. The pressure sensor made of titanium alloy material has incomparable advantages in terms of weight reduction, improving operation efficiency, and reducing operation costs, and can make the pressure sensor have higher measurement accuracy, faster response speed, and wider working temperature range. In addition, due to a series of advantages such as high specific strength, good corrosion resistance, and good heat resistance of titanium alloy, it can withstand use in more severe environments. Therefore, titanium alloy is used as a new material in the non-oil-filled pressure sensor, which improves the reliability, stability, and environmental adaptability of the pressure sensor, and at the same time improves the service life of the pressure sensor.

[0018] In some technical solutions disclosed by the present invention, the pressure sensor is integrated with assembly, encapsulation, installation, and testing. It has a small volume and occupies less space, which is more conducive to integration and installation, is suitable for use in more restricted spaces, and improves the flexibility and adaptability of system applications.

[0019] In some technical solutions disclosed by the present invention, the outer diameter size of the pressure sensor is designed to be 10 mm, achieving the purpose of making a small-size and high-performance pressure sensor. Due to its small volume and less occupied space, it is convenient for integration and installation, improves the flexibility and adaptability of the system, and can be applied to more restricted spaces or occasions with high-precision layout requirements.

[0020] In some technical solutions disclosed by the present invention, the pressure sensor adopts a non-oil-filled manufacturing process. Compared with the conventional oil-filled pressure sensor, it realizes the full-performance encapsulation and application of the chip, can eliminate the negative impact of silicone oil on pressure transmission and chip performance, and the comprehensive accuracy can reach more than 0.02%FS.

[0021] In some technical solutions disclosed by the present invention, a gold wire bonding technology is adopted to connect and conduct between the wire and the chip, and the connection is firm, thereby improving the reliability of the pressure sensor.

[0022] In some technical solutions disclosed by the present invention, the vacuum electron beam welding process is adopted for the seal welding technology between the base and the pressure nozzle, which can reduce the heat input during the welding process and prevent impurity gases in the air from mixing into the welding process. Compared with the conventional laser welding and argon arc welding processes, the welding quality can be improved, and the stability of the sensor can be further enhanced.

[0023] In some technical solutions disclosed by the present invention, the pressure nozzle adopts an integrated structure. Compared with the conventional stainless steel cylindrical pressure sensor that can only be installed and used after welding the structural parts, the pressure sensor of the present invention can be directly installed and used by utilizing the pressure nozzle without welding the installation structural parts, which can reduce the heat input amount brought by welding, reduce the overall size of the pressure sensor, and improve the installation and use efficiency of the sensor.

[0024] The pressure sensor preparation method proposed by the present invention has strong operability. The prepared pressure sensor can achieve small size, non-oil filling and light weight, and solve the problems existing in the traditional oil-filled pressure sensor, such as low output accuracy, large measurement error, poor output stability, slow response speed, narrow working temperature range, high risk of liquid leakage, and low service life. Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 It is a schematic structural diagram of the pressure sensor disclosed in the embodiment of the present invention.

[0027] In the figure, the reference numerals are: 100 - pressure sensor; 1 - base; 11 - groove cavity; 12 - wire hole; 2 - insulating solid encapsulation layer; 3 - pressure nozzle; 31 - connection seat; 32 - nozzle; 33 - buffer cavity; 34 - diversion hole; 35 - external thread section; 36 - annular groove; 4 - chip; 5 - wire; 6 - sintered glass insulating layer; 7 - gold wire; 8 - insulating ceramic ring; 81 - ceramic hole; 82 - inner ring end face; 9 - adhesive layer. Detailed Embodiments

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] One of the objectives of the present invention is to provide a novel pressure sensor. The pressure sensor adopts a non-oil-filled structure design to solve the problems existing in traditional oil-filled pressure sensors, such as low output accuracy, large measurement error, poor output stability, slow response speed, narrow working temperature range, high risk of liquid leakage, and low service life.

[0030] Another objective of the present invention is to provide a preparation method for the above-mentioned pressure sensor to solve the problems existing in traditional oil-filled pressure sensors, such as low output accuracy, large measurement error, poor output stability, slow response speed, narrow working temperature range, high risk of liquid leakage, and low service life.

[0031] To make the above objectives, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0032] Embodiment 1 As Figure 1 shown, this embodiment provides a pressure sensor 100, including a base 1, a measurement component, an insulating solid encapsulation layer 2, and a pressure nozzle 3; a groove cavity 11 is provided at the first end (the bottom end shown in Figure 1 ) of the base 1, and a wire hole 12 communicating with the groove cavity 11 is opened at the second end (the top end shown in Figure 1 ) of the base 1; the measurement component includes a chip 4 and wires 5. The chip 4 is a pressure sensing chip and is arranged in the groove cavity 11. Multiple wires 5 are electrically connected to the chip 4, and any one of the wires 5 passes through the wire hole 12 and extends outside the base 1; the insulating solid encapsulation layer 2 is arranged in the groove cavity 11 and encapsulates and fixes the above-mentioned measurement component in the groove cavity 11 to ensure the sealing performance of the periphery of the measurement component. The insulating solid encapsulation layer 2 is mainly used for pressure transmission and preventing external interference. The pressure nozzle 3 is hermetically connected to the first end of the base 1, and the pressure nozzle 3 is used to introduce the fluid to be measured into the groove cavity 11. The above-mentioned pressure sensor 100 adopts a non-oil-filled sealing structure design, but uses the insulating solid encapsulation layer 2 in the groove cavity 11 as the pressure transmission medium, which can avoid the problems of traditional oil-filled pressure sensors, such as low output accuracy, large measurement error, poor output stability, slow response speed, narrow working temperature range, high risk of oil leakage, and low service life.

[0033] In some feasible embodiments, both the base 1 and the pressure nozzle 3 are preferably made of titanium alloy structure, and the base 1 and the pressure nozzle 3 are welded. Both the base 1 and the pressure nozzle 3 are made of titanium alloy, which not only realizes the light weight of the sensor, but also titanium alloy has the advantages of corrosion resistance, high strength, etc., which can improve the service life and durability of the sensor. The base 1 and the pressure nozzle 3 are preferably welded by vacuum electron beam welding.

[0034] In some feasible embodiments, the titanium alloy base 1 is preferably prepared by a sintering process, so the titanium alloy base can also be called a "sintered seat".

[0035] In some feasible embodiments, the chip 4 adopts a chip form including but not limited to a MEMS pressure chip. The chip 4 is a conventional component in the pressure sensor, and its specific structure and functional principle are all mature technologies, which will not be elaborated here.

[0036] In some feasible embodiments, the base 1 can be a prismatic or cylindrical base, and a cylindrical base is preferably adopted. A plurality of wire holes 12 are evenly opened around the axis of the cylindrical base at the second end of the cylindrical base. Any one of the wire holes 12 is parallel to the axis of the cylindrical base, and each wire hole 12 communicates with the groove cavity 11. The number of wires 5 is the same as the number of wire holes 12, and a wire 5 passes through any one of the wire holes 12. In actual operation, generally 4 to 6 wires 5 are provided, and correspondingly 4 to 6 wire holes 12 are opened; among them, it is a better solution to provide 5 or 6 wires 5.

[0037] In some feasible embodiments, the wire 5 is preferably a kovar wire.

[0038] In some feasible embodiments, the outer diameter of the cylindrical base can be 10 mm, which realizes the small-size design of the above-mentioned non-oil-filled sensor, is suitable for a variety of installation spaces, and is more flexible and widely used.

[0039] In some feasible embodiments, a sintered glass insulating layer 6 is hermetically filled in the annular gap between any one of the wires 5 and the corresponding wire hole 12. The sintered glass insulating layer 6 can not only fix the wire 5, but also seal the annular gap between the wire 5 and the wire hole 12 to prevent external impurities or liquids from entering, which can improve the service life of the sensor. The sintered glass insulating layer 6 is preferably sintered from glass powder with a special ratio. In actual operation, first pass the wire 5 through the wire hole 12 and make the wire 5 located at the center of the wire hole 12, and then fill the wire hole 12 with glass powder and sinter it to form the above-mentioned sintered glass insulating layer 6 on the outer periphery of the wire 5.

[0040] In some feasible embodiments, the groove cavity 11 is preferably coaxial with the cylindrical base, and any cross-section of the groove cavity 11 is circular. As Figure 1As shown, preferably, the central region of the groove cavity 11 is recessed towards the second end of the cylindrical base to form a recessed region, and the chip 4 is installed in this recessed region; the annular region of the groove cavity 11 located outside the recessed region corresponds to the opening positions of the respective wire holes 12, and each wire hole 12 penetrates through this annular region to achieve communication with the groove cavity 11.

[0041] In some feasible embodiments, the pressure sensor 100 further includes an insulating ceramic ring 8, which is disposed in the groove cavity 11 and is located at the aforementioned annular region. The aforementioned annular region, the insulating ceramic ring 8, the groove cavity 11, and the cylindrical base are coaxial, and the outer ring sidewall of the insulating ceramic ring 8 is in contact or has a clearance fit with the inner sidewall of the groove cavity 11. The insulating ceramic ring 8 is provided with ceramic holes 81 corresponding one-to-one to the wire holes 12, and the wire 5 sequentially penetrates through the ceramic holes 81 and the wire holes 12; the insulating ceramic ring 8 is fixedly encapsulated in the groove cavity 11 through an insulating solid encapsulation layer 2.

[0042] In some feasible embodiments, a plurality of electrodes having the same number as the wires 5 are provided on one end face of the chip 4 facing the pressure nozzle 3, and any one wire 5 is electrically connected to the corresponding electrode through a gold wire 7; and any one gold wire 7 is arranged at an interval from the insulating ceramic ring 8, that is, each gold wire 7 does not contact the insulating ceramic ring 8. As a preferred solution, the wire 5 and the electrode of the chip 4 are connected to communicate signals by using a gold wire bonding technology, which can maintain the stability of the sensor in a high-temperature environment, thereby expanding the measurement temperature range of the sensor and overcoming the problem that the silicone oil in the traditional oil-filled pressure sensor is prone to expansion at high temperatures, thus affecting the test accuracy and response speed of the sensor.

[0043] In some feasible embodiments, in order to improve the installation firmness of the insulating ceramic ring 8 and the chip 4 with the base 1, preferably, the insulating ceramic ring 8 and the chip 4 are also fixedly bonded in the groove cavity 11 through an adhesive layer 9; the chip 4 is located at the center of the insulating ceramic ring 8, and the electrode mounting end face of the chip 4 (that is Figure 1 the bottom end face of the chip 4 shown) protrudes from the inner ring end face 82 of the insulating ceramic ring 8, and the inner ring end face 82 is the inner ring part of the end face of the insulating ceramic ring 8 facing the pressure nozzle 3. The electrode mounting end face of the chip 4 (that is Figure 1 the bottom end face of the chip 4 shown) protrudes from the inner ring end face 82 of the insulating ceramic ring 8, which can make the middle part of the gold wire 7 sag downward after the two ends of the gold wire 7 are respectively connected to the electrode and the wire 5, so as to avoid contacting the insulating ceramic ring 8.

[0044] In some feasible embodiments, as Figure 1 shown, the pressure nozzle 3 includes a connection seat 31 and a nozzle 32. The connection seat 31 is preferably a circular connection seat having the same outer diameter as the base 1. The connection seat 31 is aligned with the first end of the base 1 and sealed and welded. The first end of the connection seat 31 ( Figure 1The top end as shown is provided with a buffer cavity 33 that is hermetically docked with the groove cavity 11. The nozzle 32 is arranged at the second end of the connecting seat 31 ( Figure 1 the bottom end as shown). A diversion hole 34 is formed in the pressure nozzle 3. One end of the diversion hole 34 penetrates through the connecting seat 31 and communicates with the buffer cavity 33, and the other end of the diversion hole 34 penetrates through the nozzle 32; the end of the nozzle 32 away from the connecting seat 31 ( Figure 1 the bottom end as shown) is externally provided with an external thread section 35 for connecting an external pipeline, and the external pipeline is used to convey the fluid to be measured to the diversion hole 34; a ring groove 36 for installing a sealing gasket is arranged at the position of the nozzle 32 between the external thread section 35 and the connecting seat 31. After the pressure nozzle 3 is screwed and installed with the external pipeline through the external thread section 35, the connecting seat 31 presses the sealing gasket at the ring groove 36 against the surface of the device where the external pipeline is located, which can improve the connection sealing performance between the pressure nozzle 3 and the external pipeline and avoid the leakage of the fluid to be measured during the test, resulting in measurement errors.

[0045] In some feasible embodiments, the pressure nozzle 3 is an integrally formed part. The pressure nozzle 3 can be directly installed and connected with the external pipeline through the external thread section 35, and a sealing gasket can be installed through the ring groove 36 to ensure the connection sealing performance between the pressure nozzle 3 and the external pipeline. Through the integrated structure of the external thread section 35 and the ring groove 36, compared with the conventional stainless steel cylindrical pressure sensor that can only be installed and used after welding structural parts, the pressure sensor of this solution can be directly used without welding installation structural parts, which not only reduces the heat input amount brought by welding, but also can reduce the overall size of the pressure sensor and improve the use and installation efficiency of the sensor.

[0046] For the above-mentioned pressure sensor 100, a groove cavity 11 is arranged at the lower part of the base 1 for fixing the insulating ceramic ring 8 and the chip 4. The electrodes on the chip 4 and the wire 5 conduct electrical signals through the gold wire 7; after pouring and drying silicone gel into the groove cavity 11, the aforementioned insulating solid encapsulation layer 2 is formed, and the insulating solid encapsulation layer 2 encapsulates the gold wire 7, the wire 5 and the chip 4 in the groove cavity 11. Finally, the base 1 and the pressure nozzle 3 are docked and welded into one body by a precision welding method to obtain the pressure sensor 100. When the pressure sensor 100 is in use, the pressure nozzle 3 is first tightened with the external pipeline through the external thread section 35, and the external pipeline conveys the fluid to be measured to the diversion hole 34. The fluid to be measured enters the buffer cavity 33 after passing through the diversion hole 34, so as to act on the insulating solid encapsulation layer 2 over a large area. The insulating solid encapsulation layer 2 transmits the fluid pressure to the chip 4 to complete the measurement of the fluid pressure. The fluid to be measured includes but is not limited to liquids and gases.

[0047] The aforementioned pressure sensor 100 is an overall small-sized, oil-free, and lightweight pressure sensor, which has the advantages of high precision and long service life, and is suitable for narrow spaces and high-precision measurements. It mainly has the following beneficial effects: (1) Traditional oil-filled pressure sensors rely on oil to transmit pressure. In this solution, an oil-free sensor structure design is adopted, that is, an insulating solid encapsulation layer 2 in the groove cavity 11 is used as the pressure transmission medium, which can avoid the problems of low output accuracy, large measurement error, poor output stability, slow response speed, high oil leakage risk, and low service life existing in traditional oil-filled pressure sensors, and avoid the pollution and safety hazards caused by oil leakage. The measurement performance of oil-filled pressure sensors is closely related to the ambient temperature, and it is particularly prone to failure at high temperatures, which greatly limits the application scenarios of the sensors; while this solution uses solid materials to transmit pressure, which is less affected by the ambient temperature and can still maintain stable performance at high temperatures, with high measurement accuracy, and broadens the working temperature range of the sensor, improving the performance indicators of the pressure sensor and meeting the needs of more occasions with high-precision and wide-temperature-range layouts.

[0048] (2) The base 1 and the pressure nozzle 3 of the pressure sensor in this solution are both made of titanium alloy materials. The density of titanium alloy is only 4.54 g / cm³, and the weight of a titanium alloy pressure sensor with the same structural size is about 2 / 3 of that of a stainless steel pressure sensor, achieving the purpose of lightweight production of the pressure sensor and generally improving the working efficiency of the pressure sensor.

[0049] The pressure sensor in this solution uses titanium alloy materials, which have incomparable advantages in terms of weight reduction, improving operation efficiency, and reducing operation costs, enabling the pressure sensor to have higher measurement accuracy, faster response speed, and a wider working temperature range.

[0050] In addition, due to a series of advantages of titanium alloy such as high specific strength, good corrosion resistance, and good heat resistance, it can withstand use in more severe environments. Therefore, titanium alloy is used as a new material in oil-free pressure sensors, improving the reliability, stability, and environmental adaptability of the pressure sensor, and at the same time increasing the service life of the pressure sensor.

[0051] (3) The pressure sensor in this solution integrates assembly, encapsulation, installation, and testing in an integrated design. It is small in size and occupies less space, which is more conducive to integration and installation, is suitable for use in more restricted spaces, and improves the flexibility and adaptability of system applications.

[0052] (4) The outer diameter size of the pressure sensor in this solution is designed to be 10 mm, achieving the purpose of small-size and high-performance production of the pressure sensor. Due to its small size and less occupied space, it is convenient for integration and installation, improving the flexibility and adaptability of the system, and can be applied to more restricted spaces or occasions with high-precision layout requirements.

[0053] (5) The pressure sensor in this solution adopts a non-oil-filled manufacturing process. Compared with the conventional oil-filled pressure sensor, it realizes the full-performance encapsulation and application of the chip, can eliminate the negative impact of silicone oil on pressure transmission and chip performance, and the comprehensive accuracy can reach more than 0.02%FS.

[0054] (6) The wire bonding process between the wire 5 and the chip 4 can adopt Φ32μm gold wire and double-ball pressure welding technology, and preheat at 150°C before welding. Compared with the traditional single-ball pressure welding process, it increases the connection firmness and improves the welding strength, thus improving the reliability of the pressure sensor.

[0055] (7) The vacuum electron beam welding process is adopted for the seal welding technology between the base 1 and the pressure nozzle 3, which can reduce the heat input during the welding process and prevent impurity gases in the air from mixing into the welding process. Compared with the conventional laser welding and argon arc welding processes, it can improve the welding quality and further enhance the stability of the sensor.

[0056] (8) The pressure nozzle adopts an integrated structure. Compared with the conventional stainless steel cylindrical pressure sensor that can only be installed and used after welding the structural parts, the pressure sensor in this solution can be directly installed and used by using the pressure nozzle without welding the installation structural parts, which can reduce the heat input caused by welding, reduce the overall size of the pressure sensor, and improve the installation and use efficiency of the sensor.

[0057] In summary, the design of the pressure sensor 100 in this solution solves the problems of the traditional stainless steel oil-filled pressure sensor, such as large weight, potential oil leakage, slow response speed, narrow working temperature range, and accuracy not meeting the index requirements.

[0058] Embodiment 2 This embodiment proposes a preparation method for the pressure sensor 100 in Embodiment 1, which mainly includes the following parts: Step 1: Thread the wire 5 through the wire hole 12 of the base 1. Specifically: The wire 5 uses a kovar wire. After positioning the kovar wire in the wire hole 12 of the titanium alloy base, fill borate glass in the wire hole 12, and then fix and seal the kovar wire in the wire hole 12 through a sintering process. It is qualified if the insulation performance of the sintered glass insulation layer 6 formed by sintering is greater than 1GΩ / 500VDC.

[0059] Step 2: Install the chip 4 in the groove cavity 11. Specifically: Before installing the chip 4, the base 1, the pressure nozzle 3, and the insulating ceramic ring 8 can be cleaned with anhydrous ethanol first, and then dried at 100°C; the cleaned base 1 can also be used with a plasma cleaning device to remove the surface oxide layer.

[0060] The chip 4 is preferably a MEMS pressure chip, and its electrodes are preferably aluminum electrodes. The MEMS pressure chip uses high and low temperature resistant silicone rubber and is fixed in the middle concave area of the groove cavity 11 through die bonding technology. A glue layer 9 with a certain thickness is formed between the chip 4 and the concave area. At this time, the bottom end of the chip 4 slightly protrudes from the aforementioned inner ring end face 82.

[0061] Step 3: Install the insulating ceramic ring 8 in the groove cavity 11 and extend the wire 5 into the ceramic hole 81. Specifically: When installing the insulating ceramic ring 8, apply glue to the insulating ceramic ring 8 and align and fix it in the groove cavity 11 according to the wire hole 12, and cure it at room temperature for 24 hours. The insulating ceramic ring 8 is fixed in the groove cavity 11 through the glue layer formed by curing.

[0062] Step 4: Connect and conduct the wire 5 and the electrodes on the chip 4 through gold wire bonding technology. Specifically: The aluminum electrodes on the MEMS pressure chip and the kovar wire are connected and conducted using gold wire bonding technology. The first-piece test pull force greater than 5 gf is qualified. Based on this, the assembly of the sensor base assembly is completed.

[0063] Step 5: Pour silicone gel into the groove cavity 11 and dry it to form an insulating solid encapsulation layer 2. Specifically: In an environment with a cleanliness level of over 100,000, first fill the gap in the groove cavity 11 of the sensor base assembly and the surface of the chip 4 with silicone gel, and then pour silicone gel into the groove cavity 11 until the silicone gel submerges the chip 4, the gold wire, and the insulating ceramic ring 8. Cure it at room temperature for 48 hours. After the silicone gel cures, an insulating solid encapsulation layer 2 is formed to complete the encapsulation of the components inside the groove cavity 11.

[0064] Step 6: Weld the base 1 and the pressure nozzle 3. Specifically: Install the aforementioned sensor base assembly encapsulated with the insulating solid encapsulation layer 2 and the pressure nozzle 3 in the designed welding assembly tooling, and then seal and transfer it to the welding station to be sealed into a whole through vacuum welding technology to form a pressure sensor 100.

[0065] After that, the encapsulated pressure sensor 100 can be tested and inspected for appearance, sealing, performance, etc. to complete the product production.

[0066] In some feasible embodiments, vacuum electron beam welding is used between the base 1 and the pressure nozzle 3.

[0067] In some feasible embodiments, the gold wire bonding technology in Step 4 is preferably the double ball bonding method, and the sintering base needs to be preheated at 150 °C before bonding.

[0068] In some feasible embodiments, the silicone gel in Step 5 is an A / B component glue, which is evenly mixed in a ratio of 1:1, fills the gaps in the groove cavity 11 through the pouring method, and then is placed in an incubator and dried at 100 °C for 1 hour.

[0069] The pressure sensor 100 prepared by the above method for preparing a pressure sensor has all the characteristics of the pressure sensor 100 in Embodiment 1, which will not be repeated here.

[0070] It should be noted that the structures, ratios, sizes, etc. depicted in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in this technology to understand and read, and are not used to limit the conditions under which the present invention can be implemented. Therefore, they do not have a substantial technical meaning. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle", and "one" cited in this specification are only for the convenience of description and clarity, and are not used to limit the scope of implementation of the present invention. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope within which the present invention can be implemented.

[0071] Specific examples are used in the present invention to elaborate on the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, based on the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A pressure sensor, characterized in that: The invention comprises a base (1), a measuring component, an insulating solid packaging layer (2) and a pressure nozzle (3); the first end of the base (1) is provided with a groove cavity (11), and the second end of the base (1) is provided with a wire hole (12) connected to the groove cavity (11); the measuring component comprises a chip (4) and a wire (5); the chip (4) is arranged in the groove cavity (11), a plurality of wires (5) are electrically connected to the chip (4), and any one of the wires (5) passes through the wire hole (12) and extends out of the base (1); the insulating solid packaging layer (2) is arranged in the groove cavity (11), and the measuring component is packaged and fixed in the groove cavity (11); the pressure nozzle (3) is sealed and connected to the first end of the base (1), and the pressure nozzle (3) is used to introduce the fluid to be measured into the groove cavity (11).

2. The pressure sensor according to claim 1, characterized in that: The base (1) and the pressure nozzle (3) are both titanium alloy structures, and the base (1) and the pressure nozzle (3) are welded.

3. The pressure sensor according to claim 1 or 2, characterized in that: The base (1) is a cylindrical base, and a plurality of wire holes (12) are evenly arranged at the second end of the cylindrical base around the axis of the cylindrical base; the number of the wires (5) is the same as the number of the wire holes (12), and one wire (5) passes through any one of the wire holes (12).

4. The pressure sensor according to claim 3, characterized in that: The annular gap between any one of the wires (5) and the corresponding wire hole (12) is sealed and filled with a sintered glass insulation layer (6).

5. The pressure sensor according to claim 3, characterized in that: It also comprises an insulating ceramic ring (8), the insulating ceramic ring (8) being arranged in the groove cavity (11), and the insulating ceramic ring (8) being provided with ceramic holes (81) corresponding one to one with the wire holes (12), the wires (5) passing through the ceramic holes (81) and the wire holes (12) in sequence; the insulating ceramic ring (8) being encapsulated and fixed in the groove cavity (11) by the insulating solid encapsulation layer.

6. The pressure sensor according to claim 5, characterized in that: A plurality of electrodes having the same number as the wires (5) are arranged on an end surface of the chip (4) facing the pressure nozzle (3); any one of the wires (5) is electrically connected to the corresponding electrode via a gold wire (7); and any one of the gold wires (7) is spaced apart from the insulating ceramic ring (8).

7. The pressure sensor according to claim 6, characterized in that: The insulating ceramic ring (8) and the chip (4) are both bonded in the groove cavity (11) by means of an adhesive layer; the chip (4) is located at the center of the insulating ceramic ring (8), and the electrode mounting end face of the chip (4) protrudes from the inner ring end face (82) of the insulating ceramic ring (8), and the inner ring end face (82) is the inner ring portion of the end face of the insulating ceramic ring (8) on one side facing the pressure nozzle (3).

8. The pressure sensor according to claim 1 or 2, characterized in that: The pressure nozzle (3) comprises a connecting seat (31) and a nozzle (32), wherein the connecting seat (31) is sealingly connected to a first end of the base (1), the first end of the connecting seat (31) is provided with a buffer cavity (33) that is sealingly connected to the groove cavity (11), and the nozzle (32) is arranged at a second end of the connecting seat (31); a guide hole (34) is provided in the pressure nozzle (3), one end of the guide hole (34) passes through the connecting seat (31) and is connected to the buffer cavity (33), and the other end of the guide hole (34) passes through the nozzle (32); an external thread section (35) is arranged on the outside of an end of the nozzle (32) that is away from the connecting seat (31); and an annular groove (36) for mounting a sealing gasket is arranged between the external thread section (35) and the connecting seat (31).

9. A method for preparing the pressure sensor according to any one of claims 5 to 7, characterized in that: include: The wire (5) is passed through the wire hole (12) of the base (1); the chip (4) is installed in the groove cavity (11); the insulating ceramic ring (8) is installed in the groove cavity (11), and the wire (5) is extended into the ceramic hole (81); the wire (5) is connected to the electrode on the chip (4) by gold wire bonding technology; silicone gel is poured into the groove cavity (11) and dried to form the insulating solid packaging layer; and the base (1) and the pressure nozzle (3) are welded.

10. The method for preparing a pressure sensor according to claim 9, characterized in that: Vacuum electron beam welding is used between the base (1) and the pressure nozzle (3).

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